diff --git a/op/op.Search.php b/op/op.Search.php
index 8992cbb05..4c3463a24 100644
--- a/op/op.Search.php
+++ b/op/op.Search.php
@@ -427,7 +427,7 @@ if(isset($_GET["fullsearch"]) && $_GET["fullsearch"]) {
 			header("Content-Transfer-Encoding: binary");
 			header("Content-Length: " . filesize($filename));
 			header("Content-Disposition: attachment; filename=\"export-" .date('Y-m-d') . ".xls\"");
-			header("Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
+			header("Content-Type: application/vnd.ms-excel");
 			header("Cache-Control: must-revalidate");
 		}